SEOUL (NYTIMES) - He seemed like an ordinary passenger in the departure hall of the airport in Malaysia's capital, awaiting a four-hour flight to Macau. Moments later, he felt dizzy and was carried out on a stretcher, apparently dying from poisoned-needle punctures or perhaps a toxic liquid splashed on his face by two women who ran away.

The ruckus caused by the man's death on Monday (Feb 13) at the international airport in Kuala Lumpur was minor news until a thunderbolt from the South Korean and Malaysian news media a day later: The victim was Mr Kim Jong Nam, 45, the estranged older half-brother of Mr Kim Jong Un, the unpredictable and ruthless leader of North Korea.

The death immediately turned into an international assassination intrigue connected to the opaque regime of the Kim family, which has ruled North Korea for more than 60 years.

It came as Mr Kim Jong Un, 33, who has ordered scores of subordinates executed if he questioned their fealty, has further shaken up the ranks of his closest aides, purging the chief of the secret police less than two weeks ago.

In addition, Mr Kim Jong Un has stoked a new international crisis with a ballistic missile launching and threats of more nuclear weapons tests.

The South Korean news channel TV Chosun said that two women had stabbed Mr Kim Jong Nam with poisoned needles and fled in a taxi and that the local police were searching for them. The Star, a Malaysian newspaper, quoted the police as saying the victim had sought help from a departure hall receptionist after someone "grabbed him from behind and splashed liquid on his face."

He died as medics rushed him to a hospital.

Political experts on North Korea's politics immediately speculated that Mr Kim Jong Un had ordered the assassination of his older half-sibling, who at one time had been the heir apparent and had been favoured by China, the country's ally and principal benefactor.

"Maybe Kim Jong Nam was about to do something drastic that would either compromise the regime or the family," said Dr Jae H. Ku, director of the US-Korea Institute at the Johns Hopkins School of Advanced International Studies. "By the nature of things in North Korea, the fact that he is in the bloodline represented a threat."

Others were even more emphatic in their suspicion that Mr Kim Jong Un had been responsible, partly because Mr Kim Jong Nam had been publicly critical of the transfer of power that made his half-brother the top leader after the death of their father Kim Jong Il in 2011.

"The apparent murder today of Kim Jong Nam in Malaysia by agents of his brother is the latest explosive turn in Pyongyang's vicious palace intrigue," said Dr Nicholas Eberstadt, a political economist who specialises in North and South Korea at the American Enterprise Institute in Washington. "The question remains: Do these deadly measures secure his rule or serve to undermine it?"

There also was speculation that Mr Kim Jong Un might have ordered Mr Kim Jong Nam killed because China might have been planning to support him as a replacement for Mr Kim Jong Un, who has angered Chinese leaders with his provocative weapons and missile tests.

"Kim Jong Nam reportedly has been Beijing's favourite, which may mean one day the Chinese Communist Party may overthrow Kim Jong Un and install Kim Jong Nam," said Dr Lee Sung-yoon, a North Korea expert at Tufts University's Fletcher School of Law and Diplomacy.

The Royal Malaysia Police identified the dead man as Mr Kim Chol, an alias that South Korean officials said had been used by Mr Kim Jong Nam. A police statement said the cause of death was under investigation.

There was no immediate comment from South Korea's National Intelligence Service and its Unification Ministry. North Korea's state-run media also said nothing.

HEIR WHO FELL OUT OF FAVOUR, SUPPORTED BY CHINA

Mr Kim Jong Nam, the eldest son of the late president Kim Jong Il, had been widely considered next in line to succeed him until 2001, when he was caught trying to take his son to Tokyo Disneyland with a fake visa. He was detained for several days, then deported to China.

Other analysts in South Korea say that Mr Kim Jong Nam fell out of the succession race after his mother Sung Hae Rim was rejected by the North Korean leader, who favoured Mr Kim Jong Un's mother, Ko Young Hee. She and Mr Kim Jong Il had another son, Kim Jong Chol, who was seen at an Eric Clapton concert in London in 2015.

North Korea began grooming Mr Kim Jong Un as heir after his father had a stroke in 2008. As his youngest brother consolidated power , Mr Kim Jong Nam lived in semi-exile abroad. Until recently, he had sometimes been seen in Macau. TV Chosun said he had also been visiting Singapore and Malaysia, where he had girlfriends.

Mr Kim Jong Nam's son Han Sol had once studied in Bosnia and later in France. In an interview with a European television channel in 2012, the son said he did not know how his uncle Kim Jong Un "became a dictator."

Mr Kim Jong Nam was once questioned in Macau by a reporter about the likelihood that his half-brother would take over, and he seemed to accept his fate.

"It is my father's decision," he said. "So, once he decides, we have to support."

But at other times, he was critical of Mr Kim Jong Un's ascendance.

"I believe that my father originally was against the notion of a third generation succeeding him," Mr Kim Jong Nam, interviewed in November 2010, told the Japanese journalist Yoji Gomi in the book "My Father, Kim Jong Il, and I." "There must have been some internal reasons that made him change his mind."

Mr Kim Jong Nam also once predicted doom for his half-brother's rule while talking to reporters from Japan, North Korea's sworn enemy. His criticism fueled speculation that China and certain generals in Pyongyang, the North Korean capital, might be protecting him in case anything should go wrong with Mr Kim Jong Un's rule.

Mr Gomi said in an interview on Tuesday that the last time he had contacted Mr Kim Jong Nam, in January 2012, he had said North Korea should follow China's economic path.

China had been supporting Mr Kim Jong Nam financially for many years because in the event of Mr Kim Jong Un's death, North Koreans, indoctrinated to venerate the Kim family, would look to Mr Kim Jong Nam to step in as leader, according toMr Kang Chunnu, 61, a distant relative of the Kim family who lives in Britain.

"Kim Jong Nam is a person which China can control and the North Korean people can trust," she said by telephone.

DEATH LINKED TO KIM JONG UN'S 'REIGN OF TERROR'

There seemed little question in South Korea that Mr Kim Jong Un was behind his half-brother's death.

A spokesman for South Korea's governing Liberty Korea Party, Kim Myung Yeon, said the killing was a "naked example of Kim Jong Un's reign of terror."

Since taking power, Mr Kim Jong Un has executed more than 140 senior party and military officials deemed a threat to his authority, often ordering them killed by machine guns and even flamethrowers, according to the Institute for National Security Strategy, a research group affiliated with the South's National Intelligence Service.

Mr Thae Yong Ho, who was the North's No. 2 diplomat in London until his defection to South Korea last summer, said he had fled partly because of Mr Kim Jong Un's ruthlessness.

In 2015, South Korean officials said that General Hyon Yong Chol, the defence minister, had been executed with an anti-aircraft gun in Pyongyang after dozing off during military events and second-guessing Mr Kim Jong Un's orders.

In August last year, they said Mr Kim Jong Un found fault with a deputy premier's "disrespectful posture" during a meeting and had him executed by firing squad.

Relatives were not spared. An uncle and the country's No. 2 official, Jang Song Thaek, was executed in 2013 on charges of factionalism, corruption and sedition.

Defectors from North Korea live in fear of retaliation. In 1997, Mr Lee Han Young, a nephew of Mr Kim Jong Nam's mother, was shot and killed in Seoul. South Korean officials suspected that a North Korean agent killed Mr Lee, who had become a bitter critic of the government in Pyongyang after defecting to Seoul in 1982.

Dr Cheong Seong Chang, a longtime researcher on the Kim family, said that the killing of Mr Kim Jong Nam could be carried out only on the orders of Kim Jong Un.

Mr Ken E. Gause, a specialist in leadership studies at the CNA Corp., a research group in Alexandria, Virginia, said the assassination also might have been meant as a warning to all North Korean expatriates.

"Given the recent defections," he said, "Kim Jong Un felt the need to show that the regime could get to anyone who may be contemplating opposing the regime."

Follow ST

The Straits Times

We have been experiencing some problems with subscriber log-ins and apologise for the inconvenience caused. Until we resolve the issues, subscribers need not log in to access ST Digital articles. But a log-in is still required for our PDFs.